The industrial interest in blends

Selected examples of industrial blends have been reviewed. In each case specific reference has been made to their functional/economic justification. The area of incompatible blends is identified as the one with significant growth potential and providing the greatest scientific and technological challenge. Key to meeting this challenge is a concerted effort in three distinct areas, i.e. thermodynamics, processing and new compatibilisers.     

Tautomer chemistry of thiazolidines. 1-Thia-4-azaspiro[4,5] decanes

The thiazolidine, 1-thia-4-azaspiro[4,5] decane (Ia), which is derived from cyclohexanone and 2-aminoethanethiol (X), forms a thiazolidone (VIII) with mercaptoacetic acid more slowly and in lower yield than with 2-phenylthiazolidine, a case reported previously. A thiazolidine which is related to a non-conjugate chain tautomer such as Ic, might be expected to behave in this way. Alkylation, as another possible example of tautomer chemistry, was studied, and N-, S-, and C-alkylation were all observed under varying circumstances. Thus, thiazolidine la undergoes alkylation with methyl iodide in ethanol to form the N-methylthiazolidine (IIa), and in sodium-liquid ammonia to give the S-methyl derivative (III). In the latter case, alkylation occurs with reductive cleavage. Although no trace of other tautomer derivatives (IV, V) was to be found in the methyl iodide alkylation, I with acrylonitrile did in fact give C-alkylation. An analytically pure mixture of tautomers was obtained, from which 2-oxocyclohexanepropionitrile (VI) was isolated on hydrolysis. In a manner similar to the formation of III, IIa was S-alkylated by treatment with sodium-liquid ammonia followed by benzyl chloride to give a saturated product (XVII). Although such a process might be identified with a chain tautomer (IIb), the evidence is to the contrary, since the intermediate (XIV), which might be involved in such a process, fails to undergo a similar reduction with sodium-liquid ammonia. A greatly improved procedure for the preparation of thiazolidine (XI, 86% yield) is also reported.     

Flow of two liquids in a helix: an analogue of high pressure helical boilers

It has been shown previously (Gardner & Kubie 1976) that a two-liquid system provides a better analogue for investigating certain aspects of high pressure boiler tube hydrodynamics than air and water at atmospheric pressure. A study is presented here of the flow of $\text{n-}\text{butyl}$ acetate and water, and iso-amyl alcohol and water in helical coils and the general conclusion is that strongly stratified conditions of either completely separated phases or of drops of one phase in the other exist until velocities are high enough to produce drops sufficiently fine to be dispersed by the turbulence. The critical condition for the breakdown of the separated phases to produce drops is quantitatively correlated with the mass flowrates needed to avoid low quality dryout in both high pressure water and high pressure freon helical boilers. Some evidence is available to support two criteria indicating that low quality dryout will not be observed for sufficiently low pressures in steam-water systems and, perhaps, for small enough bore tubes.     

The preparation and properties of metallofluorene complexes of transition metals.

Metalluorene complexes (π-C₅H₅)M(CO)(C₁₂H₈) (IVa)-(IVc) and (π-C₅H₅) (CO)(C₁₂F₈) (IVd)-(IVf) (M = Co, Rh and Ir) have been prepared from reactions of the appropriate (π-cyclopentadienyl) carbonylmetal diiodides with 2,2′-dilithhiolbiphenyl (IIa) and 2,2′-dilithiooctafluorobiphenyl (IIb), respectively The triphenylphoshine substitution reactions of cobalt compounds (IVa) and (IVd) have also been studied. Reaction of (IIa) and (IIb) with norbornadieneplatinum dichloride result in the preparation of metallocyclic platinum compounds (π-C₇H₈) and (π-C₇H₈)Pt(C₁₂H₈). A reaction of (IIb) with zirconocene dichloride produces (π-C₅H₅)₂Zr(C₁₂F₈), the first example of a ziconium-containing metalofluorene.     

A systematic approach to quantitation of ephedra alkaloids in natural health products

A method for accurate determination of ephedrine (E) alkaloids in natural health products (NHP) is described. The NIST dietary supplement standard reference materials (SRMs) were selected for these studies. These SRMs comprise ground Ma Huang herb (Ephedra sinica Stapf.), a spray dried extract of the former, and commercial formulations derived from gel caps and a protein drink. The efficiency of sonication-assisted extraction and Soxhlet extraction was studied using both ammonium formate and potassium phosphate in 3% methanol as extraction media. The efficiency of SPE clean-up of the extract deteriorated rapidly when increasing amounts of sample matrix or analyte were processed, because of limited cartridge capacity. Quantitation by the method of additions was required to ensure the highest accuracy using both LC–UV and ES–LC–MS–MS techniques. Whereas the LC–UV method is more convenient and precise, the results are more questionable than ES–LC–MS–MS, because species-specific detection is not possible.